We propose to evaluate the efficacy of allogeneic bone marrow transplantation as therapy for patients with sickle cell anemia who have symptomatic disease. Bone marrow transplantation has proven to be effective therapy for a number of genetically determined diseases. The largest experience with marrow transplantation has been in the treatment of thalassemia major. Studies have demonstrated an overall event-free survival of 75% using the combination of busulfan and cyclophosphamide as a conditioning regimen. In patients under the age of 16 without hepatomegaly or portal fibrosis the 3-year event-free survival has been in excess of 90%. Overall survival for patients with sickle cell anemia has improved with supportive and preventive care measures. However, significant morbidity and expense are incurred in managing these patients. Bone marrow transplantation will be performed in patients with sickle cell anemia at risk for significant morbidity from their disease. Patients will be treated with busulfan, antithymocyte globulin and cyclophosphamide and receive an allogeneic bone marrow transplant from an HLA-identical family member. Studies will be performed to evaluate complications from the procedure such as organ toxicity, graft rejection, graft versus host disease, immunological deficiency and long- term sequelae including quality of life assessments. These studies should help define the role of bone marrow transplantation as a therapeutic modality in this disease.